What does package mean in java?

A package in Java is a collection of related code elements (such as classes, interfaces, etc.) with organization, namespace and visibility control functions. It uses reverse domain name representation and uses dots to separate elements. Elements within a package are visible in the same package by default, but visibility can be controlled through access control modifiers (public, protected, default, private). Elements in other packages can be accessed using import statements.

The meaning of Package in Java

In Java programming, package is a package that contains related classes, interfaces, A collection of enumerations and annotations that often share a common function or characteristic.

Uses

package has the following uses:

• Organize code: It groups related code into one in logical units for easy maintenance and navigation.
• Namespace: It provides a unique namespace for classes and other elements to prevent name conflicts.
• Visibility control: It controls the accessibility of elements within the package.

Creating a Package

To create a package, use the package keyword at the top of the source file, followed by the package name. For example:

<code class="java">package com.example.myapp;</code>

Naming rules

The package name should follow the following naming rules:

• Use reverse domain name notation (for example, com.example.myapp).
• Use lowercase letters.
• Separate each element with a dot (.).

Visibility rules

By default, elements in a package are visible in all classes in the same package. However, visibility can be controlled via access control modifiers:

• public: Can be accessed from any package.
• protected: Can be accessed in the same package or in a derived class.
• default (no access modifier): Accessible only within the same package.
• private: Accessible only within the class in which the element is defined.

Access other Packages

To access elements in other packages, you can use the import statement. For example:

<code class="java">import java.util.List;</code>

This will import the List class from the java.util package, allowing you to use it.

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